Blue glass with improved UV and IR absorption

Abstract

The invention is a soda-lime-silica glass composition which is blue in color and having improved UV and IR absorption. The spectral properties of the blue glass at a 4.0 mm. Thickness include: 477-494 dominant wavelength and 6-40% purity of excitation. The blue glass composition, by weight, comprises a base glass composition of: 68 to 75% SiO 2 , 10 to 18% Na 2 O, 5 to 15% CaO, 0 to 10% MgO, 0 to 5% Al 2 O 3 , and 0 to 5% K 2 O, where CaO+MgO is 6 to 15% and Na 2 O+K 2 0 is 10 to 20%; and colorants consisting essentially of: 0.4 to 2.0% total iron oxide as Fe 2 O 3 , 0.15 to 2.00% manganese oxide as MnO 2 ; 0.005 to 0.025% cobalt oxide as Co, and 0 to 1.00% titanium oxide as TiO 2 . The glass is useful for automotive or architectural applications. It preferably is made by a nitrite-free method which may desirably involve the use of a reducing agent during melting operations.

We claim: 
     
       1. A blue colored ultra violet and infra red absorbing glass composition, having a base glass composition comprising: 68 to 75% SiO 2 , 10 to 18% Na 2  O, 5 to 15% CaO, 0 to 10% MgO, 0 to 5% Al 2  O 3 , and 0 to 5% K 2  O, where CaO+MgO is 6 to 15% and Na 2  O+K 2  O is 10 to 20%; and colorants consisting essentially of: 0.4 to 2.0% total iron oxide as Fe 2  O 3  ; 0.15 to 2.00% manganese oxide as MnO 2  ; 0.005 to 0.025% cobalt oxide as Co, and 0 to 1.00% titanium oxide as TiO 2 , all percentages being based on the weight percent of the total blue glass composition; the blue glass having at a 4.0 mm. thickness: 477-494 dominant wavelength and 6-40% purity of excitation. 
     
     
       2. The blue glass composition according to claim 1 wherein the dominant wavelength is between 480 and 488 nanometers. 
     
     
       3. The blue colored glass composition according to claim 1 wherein the amount of said total iron expressed as Fe 2  O, is within the range of 0.6 to 1.2 wt. %. 
     
     
       4. The blue glass composition according to claim 1 wherein the amount of manganese compound expressed as MnO 2  is 0.2 to 0.8 wt. %. 
     
     
       5. The blue glass composition according to claim 1 wherein the wherein the purity of excitation of the blue glass is from 10 to 30%. 
     
     
       6. The blue glass composition according to claim 1 wherein the amount of cobalt oxide as Co in said blue glass composition is within the range of 0.005 to 0.015 wt. %. 
     
     
       7. The blue glass composition according to claim 1 wherein the dominant wavelength of said blue glass composition is between 482 and 485 nanometers. 
     
     
       8. The blue glass composition according to claim 1 wherein said purity of excitation of said blue glass composition is between 10 and 20%. 
     
     
       9. The blue glass composition according to claim 1 wherein said composition contains about 0.10 to 0.30 SO 3 . 
     
     
       10. The blue glass composition according to claim 1 wherein said glass at 4.0 mm thickness has the spectral properties: 20 to 70% light transmittance using Illuminant A (LTA) and less than 62% ultra violet (UV) transmittance measured over the range of 300 to 400 nanometers and less than 54% infra red (IR) transmittance over the range of 760 to 2120 nanometers. 
     
     
       11. A blue ultra violet and infra red absorbing glass composition comprising: 68 to 75% SiO 2 ,10 to 18% Na 2  O, 5 to 15% CaO, 0 to 10% MgO, 0 to 5% Al 2  O 3 , and 0 to 5% K 2  O, where CaO+MgO is 6 to 15% and Na 2  O+K 2  O is 10 to 20%; and colorants consisting essentially of: about 0.6 to 1.2% total iron oxide as Fe 2  O 3  ; about 0.2 to 0.8% manganese oxide as MnO 2  ; about 0.005 to 0.015% cobalt oxide as Co, about 0 to 1.00% titanium oxide as TiO 2 , all weight percents being based on the total weight of the blue glass composition; the blue glass having at a 4.0 mm. thickness: 480-488 dominant wavelength and 10-30% purity of excitation. 
     
     
       12. The blue glass composition according to claim 1 being manufactured with the addition of anthracite coal or other reductant as a raw material component. 
     
     
       13. The blue glass composition according to claim 1 wherein said blue glass is manufactured without the use of sodium nitrate. 
     
     
       14. An automotive or architectural glass made from the composition of claim 1 wherein the glass was floated on a molten tin bath. 
     
     
       15. An automotive or architectural glazing made from the composition of claim 1.